In [1]} and [2]}, the asymptotic uplink rate of cellular links in a massive MIMO (or D2D underlaid massive MIMO) system has been studied. As for the system considered in this paper, we can also obtain a similar result about the asymptotic uplink rate of CUs as shown in the following corollary. Since corollary REF  can be analogously verified as that in [2]}, we omit the proof process for brevity.
